- // If the run queue is not empty, then we only wake up the guy who
- // can run the thread at the head, even if there is some other
- // reason for this task to run (eg. interrupted=rtsTrue).
- if (!emptyRunQueue(cap)) {
- if (cap->run_queue_hd->bound == NULL) {
- return (task->tso == NULL);
- } else {
- return (cap->run_queue_hd->bound == task);
- }
- } else if (task->tso == NULL && !emptySparkPoolCap(cap)) {
- return rtsTrue;
+ if (task->tso != NULL) {
+ // A bound task only runs if its thread is on the run queue of
+ // the capability on which it was woken up. Otherwise, we
+ // can't be sure that we have the right capability: the thread
+ // might be woken up on some other capability, and task->cap
+ // could change under our feet.
+ return (!emptyRunQueue(cap) && cap->run_queue_hd->bound == task);
+ } else {
+ // A vanilla worker task runs if either (a) there is a
+ // lightweight thread at the head of the run queue, or (b)
+ // there are sparks to execute, or (c) there is some other
+ // global condition to check, such as threads blocked on
+ // blackholes.
+ return ((!emptyRunQueue(cap) && cap->run_queue_hd->bound == NULL)
+ || !emptySparkPoolCap(cap)
+ || globalWorkToDo());